Detection of DNA hybridization on indium tin oxide surfaces

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• 作者：Selina Moses ; Scott H. Brewer ; Stephan Kraemer ; Ryan R. Fuierer ; Lisa B. Lowe ; Chiamaka Agbasi ; Marc Sauthier ; Stefan Franzen
• 关键词：Thermography ; Electrochemistry ; Fourier-transform infrared ; Nanoparticle detection ; Stripping voltammetry
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2007
• 期刊代码：161_09254005
• 类别：et
• 出版时间：8 August 2007
• 卷：125
• 期：2
• 页码：574-580
• 文件大小：345 K

摘要

Indium tin oxide (ITO) surfaces were modified with ssDNA by coupling oligonucleotides to a monolayer of 12-phosphonododecanoic acid (12-PDA) on ITO surfaces. This coupling involved the formation of an amide bond between the carboxylic acid moiety of 12-PDA to the amine group of a 5′-aminopropyl-labeled single strand of DNA. The self-assembled monolayer of 12-PDA and surface-attached oligonucleotides were characterized by X-ray photoelectron and reflectance FTIR spectroscopy. Detection of selective surface DNA hybridization was achieved by labeling the target ssDNA with gold nanoparticles. The presence of gold nanoparticles was probed using X-ray photoelectron spectroscopy, stripping voltammetry, atomic force microscopy, thermography, photoelectrochemistry (chronoamperometry) and cyclic voltammetry (CV). CV was used to successfully detect DNA hybridization for nanoparticle concentrations as low as 10 pM when using the gold nanoparticles bound to an ITO electrode as catalysts for the electrochemical oxidation of FeCl₂. The studies described here provided the basis for surface attachment methodology for various electrochemical and thermographic sensing methods that use ITO thin films as a substrate.